1. Technical Area
The invention relates to a remote control transmitter of the type used in particular for controlling devices of entertainment electronics over a wireless link, e.g. for controlling television sets, video recorders, audio sets, slide or film projectors.
2. Description of the Prior Art
The state of the art will be explained on the basis of the following example. Assume that on the screen of a television set a cursor is to be moved up and down in a vertical direction and to and from in a horizontal direction. Remote control transmitters of the conventional types exhibit as a function selector device for triggering such movements four buttons, of which each serves to trigger one of the cursor movements mentioned. A fifth button may be provided, which when pressed moves the cursor back to its original position generally at the top left of the screen. The four or five buttons represent a function selector device which outputs selection signals to a transmission circuit, depending on the function selected by pressing one of the buttons. Depending on the function selected, the transmission circuit passes coded transmission signals to a transmission element configuration located at a side of the housing. This side with the transmission element configuration is in the remarks below referred to as the front of the housing. The transmission element configuration radiates in a preferred direction, coinciding with a direction of the housing which in the following remarks will be referred to as the longitudinal direction of the housing. The coded signals are received by the device being operated, and in accordance with the code received the selected function is executed e.g. a cursor is moved in the desired direction.
A significantly more user-friendly alternative to the familiar remote control transmitters mentioned above are remote control transmitters of the type introduced in the past few years which are constructed so that to select a function the transmitter must be moved in a certain way; for example, the housing must be tilted upwards with its longitudinal axis if a cursor is to be moved upwards, or be tilted downwards with its longitudinal axis if the cursor is to be moved downwards, or the longitudinal axis must be turned to the left or right in the horizontal plane around a vertical axis in order to trigger a movement of the cursor to the left or right respectively. In this case no button need be pressed in order to perform function selection. A remote control transmitter of this type is described, for example, in U.S. Pat. No. 4,565,999. A similar remote control transmitter, which however still exhibits a trigger button (which triggers the transmission mode of the transmitter only when it is pressed in order to reduce the drain on the transmitter battery) is known from U.S. Pat. No. 4,745,402.
The volume of stereo loudspeakers, for example, can be adjusted in a corresponding way. If the volume of the left-hand loudspeaker is to be increased, the remote control transmitter is directed not centrally to the associated control unit but turned to the left in the horizontal plane, in imitation of a human being pointing to the left-hand loudspeaker. If then a trigger button is pressed, the volume is increased for as long as the button is depressed. If the button is released and then pressed again, the volume is lowered once more. If the volume of the right-hand loudspeaker is to be altered, the remote control transmitter is correspondingly swivelled to the right in the horizontal plane, with reference to the direct direction to the control unit. Thus by turning the remote control transmitter to and from the loudspeaker in question can be selected and by pressing the trigger button the user can switch over between lowering and increasing the volume.
Remote control transmitters permitting the simple mode of operation described above, where it is not necessary to press different buttons in order to select different functions, are relatively complex in construction, since they have to generate a radiation field rather precisely defined in directional terms and which additionally must be received in directionally selective mode by a receiver on the control unit being operated. The problem presenting itself was accordingly to indicate a remote control transmitter which is simple in construction and does not require a directionally selective receiver to receive its signals.